New contributions to granite characterization by ultrasonic testing.

Ultrasound evaluation permits the state of rocks to be determined quickly and cheaply, satisfying the demands faced by today's producers of ornamental stone, such as environmental sustainability, durability and safety of use. The basic objective of the present work is to analyse and develop the usefulness of ultrasound testing in estimating the physico-mechanical properties of granite. Various parameters related to Fast Fourier Transform (FFTs) and attenuation have been extracted from some of the studies conducted (parameters which have not previously been considered in work on this topic, unlike the ultrasonic pulse velocity). The experimental study was carried out on cubic specimens of 30 cm edges using longitudinal and shear wave transducers and equipment which extended the normally used natural resonance frequency range up to 500 kHz. Additionally, a validation study of the laboratory data has been conducted and some methodological improvements have been implemented. The main contribution of the work is the analysis of linear statistical correlations between the aforementioned new ultrasound parameters and physico-mechanical properties of the granites that had not previously been studied, i.e., resistance to salt crystallization and breaking load for anchors. Being properties that directly affect the durability and safety of use of granites, these correlations consolidate ultrasonics as a nondestructive method well suited to this type of material.

Caracterizacióndde la cadena de los quesos paip y campesino en el marco del prrograma mercados campesinos: dos estudios de caso / Characterization of 'paipa' and campesino' cheeses chain in the framework of 'pprograma mercados campesinos': two cases study

Este trabajo analiza la producción y comercialización de dos variedades de queso mediante el estudio de dos casos: el primero en la vereda del Verjón (Bogotá D.C.) respecto del llamado queso 'Campesino' y el otro, en Paipa y Belén (Boyacá), con el caso del queso 'Paipa'. Los productores entrevistados forman parte del Programa Mercados Campesinos que ha servido a muchos productores de la región central de Colombia para comercializar en Bogotá sus productos agrícolas y pecuarios. En el marco de este programa se presentan dificultades de orden tecnológico que impiden que algunos productores se integren adecuadamente en él. Los principales limitantes que comparten los casos estudiados son: inestabilidad en la oferta de leche que resulta escasa para el mercado disponible para el queso; desconocimiento de la composición química de la leche puesto que la aceptación del producto se basa únicamente en la experiencia; y finalmente, los implementos y utensilios requeridos para la elaboración adecuada del queso resultan inadecuados a la luz de la normatividad sanitaria vigente. Los anteriores aspectos son esenciales para que estas pequeñas industrias de transformación cumplan con los requisitos y parámetros estipulados a nivel nacional para la elaboración y producción de derivados lácteos. Se plantean alternativas de solución a las problemáticas encontradas que involucran organizaciones de productores, entidades acompañantes del Programa Mercados Campesinos y entes gubernamentales. Una de las conclusiones principales es que la búsqueda de una denominación de origen que proteja las formas tradicionales de producir queso, mejoren la valoración de la producción campesina colombiana y brinde un apoyo adicional a los productores.

This paper shows two study cases. First located in the Village of 'El Verjon (Bogotá)', analysing the production and marketing of 'Campesino Cheese', and the other one in Paipa and Belen cities (Boyacá) with the case of 'Paipa Cheese'. Producers were participants in 'Programa Mercados Campesinos', which has been facilitating trade of crops and livestock production in Bogotá for many small farmers of Colombian Central Region. However, some difficulties have been presented, that is why some farmers are not adequately integrated. The research found that the main problems for both cases are: unpredictability in supply and quality of milk, because the milk availability for small cheese producers is insufficient, unknown chemical milk composition, and absence of implements and tools that are necessaries for proper cheese fabrication. The above topics are necessaries for small cheese producers comply requirements for standards dairy products transformation. It is argued that is necessary a good management of representatives of organizations of producers, public institutions and people related with 'Programa Mercados Campesinos', which are looking for an alternative for solving this kind of problems. For instance, an alternative could be the creation of a Protection Designation of Origin in order to protect small farmer production and a better access to market.

Factors associated with poor outcomes in patients with lupus nephritis.

The objective of this study was to identify the factors associated with important clinical outcomes in a case-control study of 213 patients with lupus nephritis. Included were 47% Hispanics, 44% African Americans and 9% Caucasians with a mean age of 28 years. Fifty-four (25%) patients reached the primary composite outcome of doubling serum creatinine, end-stage renal disease or death during a mean follow-up of 37 months. Thirty-four percent African Americans, 20% Hispanics and 10% Caucasians reached the primary composite outcome (P < 0.05). Patients reaching the composite outcome had predominantly proliferative lupus nephritis (WHO classes: 30% III, 32% IV, 18% V and 5% II, P < 0.025) with higher activity index score (7 +/- 6 versus 5 +/- 5, P < 0.05), chronicity index (CI) score (4 +/- 3 versus 2 +/- 2 unit, P < 0.025), higher baseline mean arterial pressure (MAP) (111 +/- 21 versus 102 +/- 14 mmHg, P < 0.025) and serum creatinine (1.9 +/- 1.3 versus 1.3 +/- 1.0 mg/dL, P < 0.025), but lower baseline hematocrit (29 +/- 6 versus 31 + 5%, P < 0.025) and complement C3 (54 +/- 26 versus 65 + 33 mg/dL, P < 0.025) compared to controls. More patients reaching the composite outcome had nephrotic range proteinuria compared to controls (74% versus 56%, P < 0.025). By multivariate analysis, CI (hazard ratio [95% CI] 1.18 [1.07-1.30] per point), MAP (HR 1.02 [1.00-1.03] per mmHg), and baseline serum creatinine (HR 1.26 [1.04-1.54] per mg/dL) were independently associated with the composite outcome. We concluded that hypertension and elevated serum creatinine at the time of the kidney biopsy as well as a high CI are associated with an increased the risk for chronic renal failure or death in patients with lupus nephritis.

Differential cytostatic effects of NO donors and NO producing cells.

A 3-h exposure to NO donors (spermine-NO, DETA-NO, or SNAP), or to NOS II-expressing cells (activated macrophages or EMT6 cells) reversibly inhibited DNA synthesis in K562 tumor cells. In GSH-depleted K562 cells, cytostasis remained reversible when induced by DETA-NO or NOS II activity, but became irreversible after exposure to spermine-NO or SNAP. Only SNAP and spermine-NO efficiently inhibited GAPDH, an enzyme with a critical thiol, in GSH-depleted cells. Thus, the irreversible cytostasis induced in GSH-depleted cells by spermine-NO or SNAP can be tentatively attributed to S-nitrosating or oxidizing species derived from NO. However, these species did not contribute significantly to the early antiproliferative effects of macrophages. Ribonucleotide reductase, a key enzyme in DNA synthesis. has been shown to be inhibited by NO. Supplementation of the medium with deoxyribonucleosides to bypass RNR inhibition restored DNA synthesis in target cells exposed to DETA-NO and NO-producing cells, but was inefficient for GSH-depleted cells previously submitted to spermine-NO or SNAP. These cells also exhibited a persistent depletion of the dATP pool. In conclusion, GSH depletion reveals striking qualitative differences in the nature of the toxic effectors released by various NO sources, questioning the significance of S-nitrosating or oxidizing nitrogen oxides in NOS II-dependent cytostasis.